phase!phasellCOOHCOOHHOOCH2CHaCHCH.CHNH2NH.COOHCHNH2HGlutamicacid5-Aminolevulinicacid (ALA)Porphobilinogen(PBG)COOHCOOHProtoporphyrinIxMgPhasellCH2CHCHCHNADPH,lightMMcNNHProtochlorophyllide.oxidoreductaseCH.CACHCH3ReductionsiteCOOHCO,CHCO.COOHChlorophyllide aMonovinyiprotochiorophyllideaPhytoltallPhaseIVCHCHCHCH2CH3HaCH.CCHHCO,CHFigure 3-8phytoltaiChlorophyll a
Figure 3-8
LightChlaXanthophyllCarotenenChlbDPAeReaction centreFigure 3-9Primary reactionNADP+HC
Figure 3-9 Primary reaction
STROMAThylakoidFigure 3-9-1membraneLUMENFIGURE7.18 Organizationof theproteincomplexesofthethylakoidmembrane.PhotosystemIIislocatedpredominantlyinthestacked regions ofthethylakoidmembrane;photosystemIandATP synthase arefound in theunstacked regions protruding intothestroma.Cytochromeb,f complexesare evenlydistributed.Thislateral separationofthetwophotosystemsrequiresthatelectronsLHCIIPSIICytochromePSIATPsynthaseandprotonsproducedbyphotosystemIIbetransportedaconsidtrimerb6fdimererable distance before they can be acted on by photosystem I andtheATP-coupling enzyme.(AfterAllen andForsberg2001.)
Figure 3-9-1
5-2.0P700*+AO+AI+Figure 3-10FeSkFeSA+FeSB-1.5+Fd6FNR-1.0ONADP+P680*-0.5TNADPHPheo?Cytochrome→QAbgfcomplexMCytb000CytbQ0LFeSRH20CytfLight0.5X+PC+P700④Oxygen-2evolving1.0complex1LightP68002+H+1.5Photosystem!Photosystem Il
Figure 3-10
Figure3-10-1StromaD2D1QBQAFOe/b559CP43CP47PheoPheoeP680DMSPhuMnMMnMnLumen2H2O2+4H+Figure12.12Structural model of the PsIll reaction center,a schematicrepresentation showingthe structure dominated by the two PSll reaction center proteins D and D2.Themodel is based onanalogies with the bacterial reaction center complex (see Fig12.1o).Electronsaretransferred fromP680 topheophytin(Pheo)and subsequent-lytotwoplastoquinonemolecules,Qaand QB-P68o+is reduced byZ,atyrosineresidue in the Dl subunit.The oxidation of waterbythe Mn cluster is also indi-cated.CP43andCP47,chlorophylla-bindingproteins.D1issusceptibletophoto-chemical damage and undergoes active turnover (see Chapter 14; Box 9.6)
Figure 3-10-1